C-Vita Strong. Strong C-vitamin. C-vitamin has many important functions in the body. It is needed for the normal functioning of the immune system, and additionally, it helps to reduce tiredness and fatigue. C-vitamin is also essential for the formation of collagen for the normal function of blood vessels, bones, cartilage, gums, skin, and teeth. Take the C-vitamin tablet with a meal, as C-vitamin increases the absorption of iron.